Problem: Gabriela starts counting at 20, and she counts by fours. If 20 is the 1st number that Gabriela counts. what is the 12th number that she counts?
Explanation: What is the first number that she counts? $20$ What is the second number that she counts? $\begin{align*}&20 + 4 \\ &= 24\end{align*}$ What is the third number that she counts? $\begin{align*}&20 + 4 + 4 \\ &= 20 + (2 \times 4) \\ &= 28\end{align*}$ What is the 12th number that she counts? $\begin{align*}&20 + (11\times4) \\ &= 20 + 44 \\ &= 64\end{align*}$